Dispensers for rolls or stacks of sheet material have an exit port, which usually permits one sheet material at a time to be dispensed therethrough. One typical type of sheet material dispenser is mounted such that the towel is dispensed from the underside of the dispenser. This type of dispenser is most commonly associated with the dispensing of centerflow rolled towel products in which the rolled product is dispensed from an orifice on the underside of the dispenser. Such dispensers commonly have problems with proper dispensing of such rolled product. Often too much product will dispense, as it fails to tear off in the dispenser, or the product will prematurely tear off, leaving the user with a small tab of a towel. Either of such results are considered dispensing failures.
Some have tried to improve such dispensers by various features and methods. For example, the dispensers taught in U.S. Pat. No. 5,765,718 to Grasso et al. and U.S. Pat. No. 6,869,041 to Allegre et al. each utilize a conical chute to feed the tail of the towel roll toward a constricted dispensing orifice. Such a constricted orifice is designed to cause the sheet material to tear at prescribed perforations in the sheet while not restricting the flow such to cause premature tearing before such perforations. Additionally, the dispenser of Allegre et al. utilizes a biasing member to press the sheet material against the dispensing opening with an amount of force applied to the sheet material to retain the tail in the opening and cause the sheet material to separate at the prescribed perforations in the sheet.
In U.S. Pat. No. 6,629,667 to Tramontina, another type of centerflow roll dispenser is disclosed. That patent includes one of the inventors of the present invention and is similarly assigned. In one of the dispensers disclosed by the Tramontina, the sheet material passes through a Z-shaped path, which causes the sheet material to separate as desired, without the use of a constricted opening.
One issue present with all such centerflow vertical dispensers is that such dispensers are designed to dispense best when the sheet material is pulled straight downward, along a vertical axis extending down from the dispensing opening. However, users of such dispensers often naturally dispense the sheet material at some deflection angle relative to the vertical dispensing axis. A user will often pull the towel towards themselves or will pull the towel across the dispenser as they walk past the dispenser. In either case, the user pulls at some deflection angle from the preferred vertical dispensing. Typically, the sheet material will improperly dispense, or fail to dispense, the greater the deflection angle at which the user attempts to dispense. The inventors have found that is not uncommon for a typical centerflow dispenser to fail to dispense only 5 to 8 percent of the time when a user properly dispenses with a vertical pull. However, when the user pulls on the same sheet material at an angle of 45 degrees from vertical, the rate of failures can increase upward to around 50 percent. If the angle of pull increases to around 60 degrees from vertical, typical centerflow dispensers will fail to dispense the centerflow sheet material 85 to 100 percent of dispensing attempts.